Question

name:
what is $f^{-1}(9)$?

x	f(x)
9	14
15	18
17	23
21	27
23	32

Explanation:

Step1: Recall inverse function definition

For $f^{-1}(y)$, find $x$ where $f(x)=y$.

Step2: Locate $f(x)=9$ in table

Find row with $f(x)=9$: $x=4$ when $f(x)=9$.

Answer:

4